Which element creates an ion who is LARGER in size than the original atom? Rb Rn S Ca

The element S creates an ion which is larger in size than the original atom.

Explanation:

The atomic radius of elements is a measure of the size of atoms of elements. The atomic radius is defined as one-half the distance between the nuclei of identical atoms that are bonded together. Atomic radius increases on going down the group in the period table but decreases on going rom left to right across a period in the periodic able. The increase in atomic radius on going down the group is due to the addition of an extra electron shell to successive atoms of elements in a group. However, atomic radius decreases across a period due to increase in the positive charge of the nucleus of elements in the same period.

When atoms of elements form ions, the ionic radius of the resulting ion can either increase or decrease. For positive ions, the ionic radii decreases due to  loss of electron increasing the attraction of the positive nucleus or even a complete loss of an electron shell. For anions, ionic radii increases due to gain of electrons which results in greater repulsion among neighboring electrons.

Among the elements given, rubidium (Rb), and calcium (Ca) for cations, hence, their size becomes smaller. Radon, Rn, being a noble gas is relatively inert, but forms positive ions when it does take part in reactions. Sulphur, S, however forms an anion, S²⁻, hence, its size increases.